A woman carries a sign past a McDonald's on East 125th Street and Lexington Avenue in Harlem during a protest by fast food workers and supporters for higher wages April 4, 2013 in New York. AFP PHOTO/Stan HONDASTAN HONDA/AFP/Getty Images ORIG FILE ID: 518652965 / STAN HONDA AFP/Getty Images

by Paul Davidson, USA TODAY

by Paul Davidson, USA TODAY

A recent wave of strikes by fast-food employees in four cities is expected to spread to Milwaukee Wednesday as demands for higher pay shake up an industry previously insulated from worker unrest.

Front-line, limited-service restaurant workers, a category that includes fast-food employees, earned a nationwide average $9.05 an hour in March, up 2.7% the past three years, according to the Bureau of Labor Statistics. By contrast, the pay of all private-sector non-management employees is up 5.7% in that period.

Adjusting for inflation, fast-food wages have fallen 36 cents an hour since 2010, even as the industry has raked in record profits.

Saying they can't live on such meager pay, the workers are demanding $15 an hour and the right to form unions without fear of reprisal. Although all U.S. workers legally have that freedom, many who try to organize are fired or punished with reduced hours, says Dorian Warren, an associate professor of political science and public affairs at Columbia University.

Some restaurants have said they'll trim the hours of employees this year to get below the 30-hour threshold that will make them pay health insurance, starting next January, under the new health law

Until recently, there had been no efforts to unionize fast-food employees because the industry has been beset by high turnover and largely populated by teens and young adults working in part-time or seasonal jobs. The recession and sluggish recovery, however, has given rise to a new class of adult fast-food worker who can't find other employment.

"It's a job for adults supporting families," says Tsedeye Gebreselassie, staff attorney for the National Employment Law Project.

The ranks of limited-service restaurant workers have increased 11.5% to 3.8 million since the job market hit bottom in February 2010, nearly twice the rate of all private employees.

Since early April, fast-food workers in New York, Chicago, St. Louis and Detroit have staged one-day walkouts and rallies. In Milwaukee,180 workers at outlets such as McDonald's, Burger King, Taco Bell and KFC are expected to walk off the job.

"We're inspired by what's happening in other cities," says Jennifer Epps-Addison, an official at Citizen Action of Wisconsin, one of the groups coordinating the protest, which unlike the others, will include some retail workers.

Milwaukee Burger King employee Tessie Harrell says she earned the state minimum wage of $7.25 an hour from 2008 through 2012, even after she was promoted to shift supervisor in 2011. Last year, she got a raise to $8.25 an hour. But she says that's not enough to pay the $650 monthly rent on her two-bedroom apartment and support her six children.

"I can't afford to buy my kids shoes," says Harrell, 34, who gets food stamps and $150 a month from her mother. "There's no way I should be struggling to make ends meet."

In a statement, Burger King said its restaurants "have provided an entry point into the workforce for millions of Americans," including many franchisees. Burger King and McDonald's say their wages are in line with the rest of the fast-food industry.

Job actions in other cities already have made an impact. In New York, half the 70 restaurants affected by walkouts in November and early April have boosted wages from 25 cents to up to $2 an hour, says Jonathan Westin, head of New York Communities for Change.

In St. Louis, local clergy accompanied striking workers back to their jobs last week to ensure they wouldn't be fired, says Martin Rafanan, head of the local workers' campaign, "St. Louis Can't Survive on $7.35."

Workers, he says, have begun to feel empowered. "We are much stronger," he says.